Not only morphological and immunohistochemical examinations, but also cytogenetical investigations for IDH1/2 mutation, 1p/19q loss, and PTEN alteration, are strongly supportive methods for the differential diagnosis of small cell glioblastoma and anaplastic oligodendroglioma.
Univariate analysis was followed by multivariate analysis according to a Cox model. p14(ARF), p16(INK4A) and PTEN expressions, and 10p 10q23, 10q26 and 13q LOH for the entire cohort, hTERT expression for high-grade tumours, EGFR for glioblastomas, 10q26 LOH for grade III tumours and anaplastic oligodendrogliomas were found to be correlated with overall survival on univariate analysis and age and grade on multivariate analysis only.
Besides the wealth of data elucidating the functional roles of Pten, recent studies suggest a diagnostic significance of PTEN gene alterations as a molecular marker for poor prognosis in anaplastic astrocytomas and anaplastic oligodendrogliomas.
We investigated 47 glioblastomas (GBM), 14 anaplastic astrocytomas (AA), 6 non-pilocytic low-grade astrocytomas (LGA), 21 low-grade and anaplastic oligodendrogliomas (O) and oligoastrocytomas (OA), and 3 ependymomas (E) for mutation of the PTEN gene using denaturing gradient gel electrophoresis (DGGE) followed by DNA sequencing.